FET is open source free software for automatically scheduling the
timetable of a school, high-school or university. It uses a fast
and efficient timetabling algorithm.

Usually, FET is able to solve a complicated timetable in maximum
5-20 minutes. For simpler timetables, it may take a shorter time,
under 5 minutes (in some cases, a matter of seconds). For extremely
difficult timetables, it may take a longer time, a matter of hours.

FET can mean "Free Educational Timetabling" (the "E" in the middle
may also stand for other words, based on your personal preference).

WWW: https://lalescu.ro/liviu/fet/